Skip to main content

Full text of "Text Book Of Mechanical Engineering"

See other formats

Universal Flanging Press.                     303

fourth  ram   D raises and balances the vertical  rams A and B,

having a constant pressure supply; so that the rarns A and B only

rise when opened to exhaust, one or other, or both.    Yet a fifth

ram E serves as vice during single-heat flanging.    Referring to the

enlarged sections, the ram A is seen to be hollow, riding upon a

smaller fixed  ram  F.     Ordinarily  the  water   only  enters   the

annular space round the small ram, but on releasing plug G it

passes down the centre tube and then exerts a pressure on the

whole area of the large ram, a variable power being thus obtained

The horizontal ram c is of piston form with a tubular continuation

to a smaller piston H, upon which there is a constant pressure, so

the return is effected when c is opened to exhaust.    Any special

forms  of dies may be applied at j,  K, and L, and the guide

bracket M is removable.     The valve-box has five levers,  each

working both pressure and exhaust,  i for ram A, 2 for ram B, 3

for ram c, 4 for ram E, and 5 for an hydraulic crane to lift the

plates (see A, Plate XIV.).    A plate N is being flanged on the

progressive method.     It is slewed by crane, laid on a curved

hearth (B Plate, XIV.), and heated for a few feet along its edge,

then transferred to the block P and flanged as described, rams

A, B, c being applied in succession.    This is done foot by foot

until the heated portion is all flanged;   a new heat then taken,

and the work continued as before.    When flanging with complete

dies, the upper die is fastened to the rams A and B, as shewn at R,

and the lower die placed on the table.   The hot plate being laid                     jj

on the lower die, the vice ram E is first-raised and the upper                     I

rams then lowered; the flanging pressure is therefore the differ-

ence of that upon the lower and upper rams. Any kind of flanging
can be performed by this machine by using suitable dies,

Drilling Machines, for boiler work, vary greatly in their
construction. Except for the Radial machine they are all
designed to drill ' in position/ and their form depends on the
kind of work to be done. When possible they are made ex-
peditious by the use of more than one drilling head, a necessity
in view of the krge number of holes to be drilled.

Radial Drill—This has been already described at p. 167.
Opinions, differ regarding the best construction, but in almost any
form It is &a extrenaely useful tool for boilermakers. An inter-